Vitamin C
Also known as: L-Ascorbic Acid, Ascorbic acid, Ascorbate, Sodium ascorbate, Calcium ascorbate, Ascorbyl palmitate, Ester-C
This ingredient is classified as unclassified risk (GIRI score: 1.5/10).
Safety Profile
Known Safety Concerns
- Diarrhoea at >2,000 mg/day; oxalate stone risk with chronic high doses; caution in G6PD deficiency and haemochromatosis
Contraindications
- Diarrhoea at >2,000 mg/day; oxalate stone risk with chronic high doses; caution in G6PD deficiency and haemochromatosis
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
Vitamin C (L-Ascorbic Acid) is an essential water-soluble antioxidant vitamin. Core functions: (1) Collagen biosynthesis — mandatory cofactor for prolyl hydroxylase and lysyl hydroxylase enzymes that hydroxylate collagen proline and lysine residues for stable triple-helix formation; deficiency causes scurvy; (2) Antioxidant — regenerates Vitamin E; quenches reactive oxygen species; (3) Immune function — T-cell proliferation, neutrophil chemotaxis, interferon synthesis, NK cell activity; (4) Non-haem iron absorption enhancement — converts Fe³⁺ to Fe²⁺ for intestinal absorption; (5) Neurotransmitter synthesis — cofactor for dopamine beta-hydroxylase (noradrenaline synthesis) and carnitine biosynthesis. EFSA-approved health claims include collagen formation, immune function, and fatigue reduction. Generally very safe. High doses (>2,000 mg/day) may cause osmotic diarrhoea (threshold varies individually). Persons with G6PD deficiency or haemochromatosis should use caution. Oxalate kidney stones: high-dose Vitamin C (>1,000 mg/day) increases urinary oxalate — caution in individuals with kidney stone history. May interfere with some laboratory tests at pharmacological doses. Correctly paired with Collagen supplements (EFSA claim: “Vitamin C contributes to normal collagen formation for normal function of skin”).
Biological and Chemical Classification
Information not yet available for this ingredient profile.
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Executive Summary — Ingredient Assessment
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or RCT)
- Main clinical benefit observed: Vitamins & Minerals
- Evidence consistency: High consistency across studies (100%)
- Diarrhoea at >2,000 mg/day; oxalate stone risk with chronic high doses; caution in G6PD deficiency and haemochromatosis
The available scientific evidence for Vitamin C indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.
Total SETI Score
High risk| Evidence quality | 10/40 |
| Evidence consistency | 20/20 |
| Safety signals | 0/20 |
| Study recency | 10/10 |
| Evidence transparency | 10/10 |
Evidence Summary
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or systematic review)
- 0 studies identified benefits or no safety concern (GREEN)
- 10 studies reported limited or advisory safety evidence (YELLOW)
Evidence Policy
Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.
Last updated: 08 აპრ 2026, 09:57
Evidence Distribution
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Observational / other LOW evidence YELLOWModulation of oxidative biomarkers and carbohydrate metabolic enzyme activity byHypsizygusulmariuspolysaccharide in Streptozotocin/nicotinamide-induced diabeticrats. ↗Govindan S et al.. Modulation of oxidative biomarkers and carbohydrate metabolic enzyme activity byHypsizygusulmariuspolysaccharide in Streptozotocin/nicotinamide-induced diabeticrats.. Fitoterapia. 2026. PMID:41946413.PMID 41946413 ↗Journal FitoterapiaYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41946413/
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Observational / other LOW evidence YELLOWSynthesis and characterization of NiTiOu2083-L-ornithine nanoparticles and their antibacterial, antifungal, antioxidant activities, and zebrafish biocompatibility. ↗Sandilya M et al.. Synthesis and characterization of NiTiOu2083-L-ornithine nanoparticles and their antibacterial, antifungal, antioxidant activities, and zebrafish biocompatibility.. Naunyn Schmiedebergs Arch Pharmacol. 2026. PMID:41945138.PMID 41945138 ↗Journal Naunyn Schmiedebergs Arch PharmacolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41945138/
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Observational / other LOW evidence YELLOWEngineering phosphoribosylpyrophosphate synthetase in Methylobacterium radiotolerans for lettuce growth and quality enhancement. ↗Zhang LY et al.. Engineering phosphoribosylpyrophosphate synthetase in Methylobacterium radiotolerans for lettuce growth and quality enhancement.. Arch Microbiol. 2026. PMID:41945108.PMID 41945108 ↗Journal Arch MicrobiolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41945108/
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Observational / other LOW evidence YELLOWTrends in Use of IV Vitamin C Among Patients With Sepsis: Erratum. ↗Segall RE et al.. Trends in Use of IV Vitamin C Among Patients With Sepsis: Erratum.. Crit Care Med. 2026. PMID:41944712.PMID 41944712 ↗Journal Crit Care MedYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41944712/
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Observational / other LOW evidence YELLOWEvaluation of the underutilized Malpighia glabra L. fruits as a future functional food: nutritional composition, phenolic profile, biological activities, and synergistic effects… ↗Kemsawasd V et al.. Evaluation of the underutilized Malpighia glabra L. fruits as a future functional food: nutritional composition, phenolic profile, biological activities, and synergistic effects with pharmaceutical drugs.. Food Funct. 2026. PMID:41944642.PMID 41944642 ↗Journal Food FunctYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41944642/
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Observational / other LOW evidence YELLOWAn in-vitro study to characterise analytical interference caused by sodium ascorbate with point-of-care measurement of lactate and glucose. ↗Webber T et al.. An in-vitro study to characterise analytical interference caused by sodium ascorbate with point-of-care measurement of lactate and glucose.. Crit Care Resusc. 2026. PMID:41940314.PMID 41940314 ↗Journal Crit Care ResuscYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41940314/
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Observational / other LOW evidence YELLOWIntravenous vitamin C for bleeding control in elective C-sections: a randomized clinical trial study. ↗Khakifirooz B et al.. Intravenous vitamin C for bleeding control in elective C-sections: a randomized clinical trial study.. Ann Med Surg (Lond). 2026. PMID:41939119.PMID 41939119 ↗Journal Ann Med Surg (Lond)Year 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41939119/
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Observational / other LOW evidence YELLOWPhotocatalytic Semireduction of Propiolamides in Microheterogeneous Solutions via Alkyne Radical Anions. ↗Wang J et al.. Photocatalytic Semireduction of Propiolamides in Microheterogeneous Solutions via Alkyne Radical Anions.. Org Lett. 2026. PMID:41937348.PMID 41937348 ↗Journal Org LettYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41937348/
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Observational / other LOW evidence YELLOWMulti-omics approach reveals the molecular basis of ToMMV-induced resistance and its effects on tomato fruit quality. ↗Wang Y et al.. Multi-omics approach reveals the molecular basis of ToMMV-induced resistance and its effects on tomato fruit quality.. Food Chem. 2026. PMID:41936782.PMID 41936782 ↗Journal Food ChemYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41936782/
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Observational / other LOW evidence YELLOWThe effect of dietary factors and nutrients on osseointegration, dental implant success and survival: a scoping review. ↗Sodnom-Ish B et al.. The effect of dietary factors and nutrients on osseointegration, dental implant success and survival: a scoping review.. Int J Implant Dent. 2026. PMID:41936654.PMID 41936654 ↗Journal Int J Implant DentYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41936654/
Score Transparency
0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.
Method: Q = number of approved references ÷ 10 (capped at 1.0)
Limited — mostly case reports or animal studies
Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.
Mixed or neutral — roughly equal benefit and risk signals
Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.
One or more monitoring-level safety signals active
Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.
Final GIRI Score for Vitamin C. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
Full methodology & data sources
The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.
- References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
- Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
- Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
- Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Low classification for Vitamin C
A score of 1.5 places this ingredient in the Low band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
0 approved references.
Limited — mostly case reports or animal studies (Level 4–5).
Neutral or mixed — benefit and risk signals roughly balanced.
No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.
No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).
How are the Low / Moderate / High / Critical thresholds defined?
The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:
| Level | Score | Meaning |
|---|---|---|
| LOW | 0.0 – 2.9 | Sparse or predominantly beneficial evidence. No active safety alerts. |
| MODERATE | 3.0 – 5.4 | Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups. |
| HIGH | 5.5 – 7.4 | Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended. |
| CRITICAL | 7.5 – 10 | Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision. |
Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.